1. Field of the Invention
This invention relates to a grounding structure in a novel slide tray. More particularly, it relates to a technique whereby electrical components loaded on a slide tray can be grounded to a main body portion with the slide tray having been pulled forward via an opening surface of a casing of the main body portion.
2. Description of the Related Art
A certain type of electronic equipment, such as an optical disc reproducing apparatus, has a tray that can be pulled out of the casing of the main body portion thereof.
In a certain type of optical disc reproducing apparatus, electrical components, such as an optical pickup or a feed motor, in addition to a spindle motor, are loaded on the slide tray for reducing the thickness, or height, of the overall apparatus. In such slide tray, the electrical components need to be grounded to the side of a main body portion of the apparatus.
If, in the state in which the slide tray a has been pulled out of the casing b of the main body portion, the slide tray a and the casing b have overlapping portions c shown shaded in FIG. 1, the contact portions of the slide tray a and the casing b may be formed of an electrically conductive material in the overlapping portion c for grounding the electrical components to the main body portion via the contact portion.
If the overlapping portion c is provided between the slide tray a and the casing b, since it is necessary to enable mounting/dismounting operations to be carried out in the pulled out state of the slide tray, the overlapping portion c represents a redundant portion. The size of the slide tray a is increased in depth by an amount corresponding to the overlapping portion c thus increasing in depth of the casing of the main body portion housing the tray.
For reducing in depth of the optical disc reproducing apparatus, it has been envisaged to use slide rails d, d, as shown in FIG. 2.
Specifically, the slide rails d, d, slidably supported on both lateral sides of the slide tray a, are slidably supported on both inner lateral sides of casing b, b for supporting the slide tray a on the casing b so that the slide tray a can be pulled forward via an opening surface e.
By so doing, no overlapping portion is left between the slide tray a and the casing b, when the slide tray a has been pulled out of the casing b on the main body portion, thus reducing in depth of the apparatus.
Meanwhile, there is a problem if, with the use of the slide rails d, d, these slide rails are formed of electrically conductive metal.
That is, since there is no overlapping portion between the slide tray a and the casing b, when the slide tray a has been pulled out of the casing b, it may be contemplated to form the lateral sides of the slide rail a and the inner lateral sides of the casing b of an electrically conductive metal and to form the slide rails d, d of an electrically conducive metal for enabling electrical conduction between the slide tray a and the casing via slide rails d, d for grounding the electrical components loaded on the slide tray a, as shown in FIG. 2.
However, if the slide contact members a, b, d and d are formed of electrically conducive metal, fine chips of these components are produced due to sliding contact between the components a, b, d, d, as a result of repeated sliding movements of the slide tray a. Since these chips are electrically conductive, they become attached to conductors of the circuit to produce shorting.
For preventing the electrically conductive chips from being produced and for improving sliding properties, the slide rails d, d need to be formed of electrically nonconductive materials, such as synthetic resin.
If the slide rails d, d are formed of electrically nonconductive materials, the electrically conductive chips are prevented from being produced and the sliding performance can be raised. However, electrical conduction cannot be maintained between the slide tray a and the casing b, such that it becomes impossible to assure grounding of the electrical components loaded on the slide tray.
Since a flexible printed circuit board is used as electrical feed means for the electrical components loaded on the slide tray a, grounding may be realized through the flexible printed circuit board. However, due to various constraints, grounding through the flexible printed circuit board leads to shortage in capacity, such that sufficient grounding cannot be assured.